Hollow blow molding machine feed inlet method, standard, distribution of these factors directly affect the direction of the flow, density distribution, the role of compression and compression and shaping time. The direct feed port and the feed inlet section are large (especially thick section), but the direction is small, but the direction is small. Close to the feed inlet or parallel to the direction of the material flow is shortened.

Molding conditions high mold temperature, melt cooling slow, high density, shorten the large, especially for the crystallization of the material is due to the high degree of crystallinity, volume changes, so shorten the larger. The distribution of mold temperature is also related to the cooling and density uniformity of the inside and outside of the blow molding box, which directly affects the size and direction of each part. In addition, adhere to the pressure and time to shorten the impact is greater, the pressure is large, the hour is long, but the reduction of the direction of large. High injection pressure, melt viscosity difference, interlaminar shear stress is small, after stripping the elastic rebound, so shortening also can be reduced, high temperature material, shortening, but the direction of small. Therefore, the molding temperature, pressure, injection speed and cooling time and other factors can also be appropriately changed to reduce the blow molding box. Mold descr1ption according to a variety of plastic shortening plan, blow molding box wall thickness, shape, feed mouth method standards and distribution, according to the experience to determine the blow molding box of each part of the shortening rate, and then accounting cavity standard. High precision blow molding box and difficult to grasp the shortening rate, the general should be described with the following methods:

A, and then try to change the appropriate conditions and skills can be slightly modified to shorten the value to meet the needs of blow molding box.

Two, according to the practice to shorten the mold.

Three, the blow molding box outside diameter to take a smaller reduction rate, the diameter of the larger shortening rate, in order to leave the test after the modification of the situation. China resin R online for the construction of China's largest database of resin work hard!

Four, to dispose of the blow molding box after the disposal of the decision to change the standard situation (measurement must be 24 hours after the release).

In five, the test method to determine the gating system, standards and molding conditions.

When the blow molding box is characterized in that the surface of the molten material and the contact surface of the cavity surface is cooled to form a low density solid shell. Because of the poor thermal conductivity of the plastic, the inner layer of the blow molding box is slowly cooled to form a large high-density solid layer. Therefore, the wall thickness, slow cooling, high density layer thickness is shortened. In addition, there are no embedded and embedded pieces of the program, the amount of direct impact on the direction of the flow, density distribution and the size of the resistance to shorten, etc., so the characteristics of the blow molding box to shorten the size, directivity greater impact

In the production of blow molding machine box molding blow molding process because of the presence of crystallization shape volume changes, internal stress, freezing box should be left in the blow force, strong molecular orientation and other factors, and thus the thermosetting plastic than shortening rate greatly, shortening plan width, obvious direction, and shortening rate after molding, shorten the annealing or wet after disposal generally than thermosetting plastic.